1. Trefts E, Gannon M, Wasserman DH. The liver. Curr Biol. 2017;27(21):R1147-R1151. doi:10.1016/j.cub.2017.09.019. Accessed 23 June 2021. Available from: https://doi.org/10.1016/j.cub.2017.09.019
2. Le J. Drug Metabolism. Accessed 23 June 2021. Available from: https://www.msdmanuals.com/professional/clinical-pharmacology/pharmacokinetics/drug-metabolism#v50215772
3. Hamoud AR, Weaver L, Stec DE, Hinds TD Jr. Bilirubin in the Liver-Gut Signaling Axis. Trends Endocrinol Metab. 2018;29(3):140-150. doi:10.1016/j.tem.2018.01.002. Accessed 23 June 2021. Available from: https://doi.org/10.1016/j.tem.2018.01.002
4. Nguyen-Lefebvre AT, Horuzsko A. Kupffer Cell Metabolism and Function. J Enzymol Metab. 2015;1(1):101. Accessed 23 June 2021. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/pmc4771376/
5. Cocciolillo, S., Sebastiani, G., Blostein, M., & Pantopoulos, K. (2020). Liver Hormones. Hormonal Signaling in Biology and Medicine, 425–444. doi: 10.1016/b978-0-12-813814-4.00018-3. Accessed 23 June 2021. Available from: https://doi.org/ 10.1016/b978-0-12-813814-4.00018-3
6. Heinz S, Braspenning J. Measurement of Blood Coagulation Factor Synthesis in Cultures of Human Hepatocytes. Methods Mol Biol. 2015;1250:309-316. doi:10.1007/978-1-4939-2074-7_23. Accessed 23 June 2021. Available from: https://doi.org/10.1007/978-1-4939-2074-7_23.
7. British Liver Trust. Liver blood tests (formally known as liver function tests - LFTs). Accessed 24 June 2021. Available from: https://britishlivertrust.org.uk/information-and-support/living-with-a-liver-condition/liver-blood-tests/
8. Woreta TA, Alqahtani SA. Evaluation of abnormal liver tests. Med Clin North Am. 2014;98(1):1-16. doi:10.1016/j.mcna.2013.09.005. Accessed 23 June 2021. Available from: https://doi.org/10.1016/j.mcna.2013.09.005
9. Phillips J, Henderson AC. Hemolytic Anemia: Evaluation and Differential Diagnosis. Am Fam Physician. 2018 Sep 15;98(6):354-361. PMID: 30215915.
10. Almasaudi AS, Dolan RD, Edwards CA, McMillan DC. Hypoalbuminemia Reflects Nutritional Risk, Body Composition and Systemic Inflammation and Is Independently Associated with Survival in Patients with Colorectal Cancer. Cancers (Basel). 2020;12(7):1986. Published 2020 Jul 21. doi:10.3390/cancers12071986. Accessed 24 June 2021. Available from: https://doi.org/10.3390/cancers12071986
11. Limdi JK, Hyde GM. Evaluation of abnormal liver function tests. Postgrad Med J. 2003;79(932):307-312. doi:10.1136/pmj.79.932.307. Accessed 27 June 2021. Available from: https://doi.org/10.1136/pmj.79.932.307
12. Public Health England. Liver disease: applying All Our Health. Accessed 26 June 2021. Available from: https://www.gov.uk/government/publications/liver-disease-applying-all-our-health/liver-disease-applying-all-our-health
13. Rocco A, Compare D, Angrisani D, Sanduzzi Zamparelli M, Nardone G. Alcoholic disease: liver and beyond. World J Gastroenterol. 2014;20(40):14652-14659. doi:10.3748/wjg.v20.i40.14652. Accessed 23 June 2021. Available from: https://doi.org/10.3748/wjg.v20.i40.14652
14. British Liver Trust. The alarming impact of liver disease in the UK Facts and statistics. Accessed 26 June 2021. Available from: https://www.britishlivertrust.org.uk/wp-content/uploads/The-alarming-impact-of-liver-disease-FINAL-June-2019.pdf
15. National Health Service (NHS). Hepatitis A vaccination. Accessed 26 June 2021. Available from: https://www.nhs.uk/conditions/hepatitis-a/vaccination/
16. NHS. Hepatitis B vaccine. Accessed 26 June 2021. Available from: https://www.nhs.uk/conditions/vaccinations/hepatitis-b-vaccine
17. British Liver Trust. Looking after your liver. Accessed 26 June 2021. Available from: https://britishlivertrust.org.uk/information-and-support/liver-health-2/love-your-liver/looking-after-your-liver/
18. Macken L, Gelson W, Priest M, et al. Efficacy of direct-acting antivirals: UK real-world data from a well-characterised predominantly cirrhotic HCV cohort. J Med Virol. 2019;91(11):1979-1988. doi:10.1002/jmv.25552. Accessed 27 June 2021. Available from: https://doi.org/10.1002/jmv.25552
19. Medicines and Healthcare products Regulatory Agency. Direct-acting antivirals to treat chronic hepatitis C: risk of interaction with vitamin K antagonists and changes in INR. Accessed 27 June 2021. Available from: https://www.gov.uk/drug-safety-update/direct-acting-antivirals-to-treat-chronic-hepatitis-c-risk-of-interaction-with-vitamin-k-antagonists-and-changes-in-inr
     

Cirrhosis is commonly called “end-stage liver disease” and is mistakenly believed to be irreversible. While the scarring tissue will not disappear on its own, the liver may improve its functions once the damaging factor is removed.[12] Therefore, people with liver damage will also benefit from avoiding alcohol and having a healthy lifestyle. Preventing viral hepatitis is extremely important: patients with liver disease are recommended to get vaccinated against hepatitis A and B if they have not become infected in the past.

People with liver damage caused by hepatitis C, if indicated, may receive treatment with direct-acting antivirals (boceprevir, daclatasvir, dasabuvir, etc.). A study from the United Kingdom, which included patients with cirrhosis, found the overall curative efficacy of these treatments to be around 91%.[18] If you receive warfarin or other vitamin K antagonists, you should inform your physician before receiving direct-acting antivirals.[19]

When managing an existing condition or attempting to reverse damage, you can monitor improvements using a liver test at home.
 

It can take 20 years for chronic liver damage to produce detectable symptoms; considering this, action must be taken early. Check your health first using a liver blood test kit to highlight concerns. Most cases of liver disease can be prevented through accessible methods: hepatitis prevention and a healthy lifestyle.[14]

• Viral hepatitis:
  • Hepatitis A vaccine is not routinely administered in the UK. It is recommended for people with chronic liver disease, high-risk workers, or those planning to travel to regions with high infection rates.[15]
  • Hepatitis B vaccine is included in the 6-in-1 vaccine offered to babies in the UK (August 2017 onwards). Your GP may vaccinate you if you consider you require the vaccine.[16]
  • Aside from vaccines, viral hepatitis is prevented by not sharing drug equipment, razors, and toothbrushes, using condoms during sex, and avoiding unlicensed tattoo or piercing studios.[17]
• Lifestyle:[17]
  • Limit alcohol to 14 units per week. The fewer drinks the better.
  • Try to have at least 3 alcohol-free days in a row per week.
  • Exercise.
  • Have a balanced diet.
     

Alcohol is one of the most important risk factors for disease and disability in general. This statement holds especially true for its main victim, the liver, which is the organ most responsible for metabolising ethanol. Alcohol, as well as its metabolites (by-products), act as hepatotoxins capable of directly damaging the liver. For example, acetaldehyde triggers inflammation and fibrosis; it is also capable of binding to proteins and DNA from liver cells, which may trigger immune responses against the hepatic tissues.[13]

Alcohol also damages the liver indirectly through multiple mechanisms. It acts synergistically with the human immunodeficiency virus (HIV) and hepatitis viruses B and C. Alcohol also promotes alcohol-related liver damage in patients with haemochromatosis and non-alcoholic fatty liver. The oesophagus, stomach, intestines, and pancreas are damaged by alcohol too, disrupting gastrointestinal function and, indirectly, damaging the liver.[13]

a) Early warnings

• Loss of appetite.
• Unwanted or unexplained loss of weight.
• Loss of muscular mass.
• Feeling tired, weak, or ill most of the time.
• Nausea and vomiting.
• Tenderness, discomfort, or pain in the liver area (upper right side of the abdomen).
• Sleeping disorders.
• Reddened skin on the palms.

b) Symptoms of liver disease

• Swelling of the lower limbs (legs, ankles, and feet) and abdomen (ascites).
• Hair loss.
• Yellowed skin and mucous membranes, such as the white of the eye or inside the mouth (jaundice).
• Alteration of sexual characteristics, such as enlarged breasts in men and irregular menstrual cycles in women.
• Lowered sexual desire (libido).
• Itchy skin.
• Frequent bruising.
• Bleeding disorders, such as nosebleeds or prolonged bleeding.
• Darkened urine and pale stools.

c) Severe signs and symptoms

• Vomiting blood.
• Shortness of breath.
• Black stools.
• Confusion.
• High fever.
   

Despite being the body’s largest solid organ and performing multiple vital functions, the purpose of the liver is commonly misunderstood. Among its primary functions, the liver has to manage macronutrients (carbohydrates, proteins, and fat), representing a critical hub for lipid and cholesterol metabolism; however, it’s capable of much more.[1]

The liver can be seen as the body’s factory: it takes the major components of your diet and turns them into a readily available energy source or integrates them into an accessible storage system. Upon feeding, the liver favours the conversion of glucose to glycogen, lipids to fatty tissue, and amino acids to proteins (albumin and globulins). Furthermore, the liver is essential for the intestinal absorption of lipids (including fat-soluble vitamins like vitamin A, D, E, and K)[1] and represents the primary site for the metabolism of various drugs[1][2] and body substances, such as bilirubin.[3]

The immune and endocrine systems are linked to the liver, too. It has its own immune cells (Kupffer cells)[4] and produces the hormones angiotensinogen (blood pressure regulator), hepcidin (controls iron metabolism), insulin-like growth factors (growth and metabolism controller), and thrombopoietin (promotes platelet production).[5] Finally, the liver regulates the production of blood coagulation factors, a vital function that allows the uninterrupted flow of blood to every organ.[6]

Given this complex functionality, assessing liver health requires a blood test, which can be conducted using a liver test at home.
 

The normal range is the term used for the range of liver function test values seen in 95% of the healthy population. The exact values may depend on your age, sex and the laboratory used for your liver function blood test.

• Normal levels of albumin and globulins say a lot about good protein production in the liver, but they also mean that the body is receiving the right amount and variety of amino acids (from dietary protein) to build up albumin, globulins, and other hepatic proteins.[1]
• Bilirubin is kept at a normal range thanks to the liver. A normal bilirubin value depends on good blood flow in and out of the liver, adequate liver function, and unobstructed bile flow out of the liver.[8]
• Aminotransferases and ALP can be detected if liver cells are injured or destroyed. The levels detected in normal ranges are expected due to normal cellular turnover

However, these values do not blindly translate into good liver health without exceptions: if you are presenting signs, symptoms, or other findings that are attributable to liver disease, further medical assistance may be required.

Abnormal liver function, as reflected by altered liver function tests, means that the liver is:[11]

• Unable to properly process and/or excrete bilirubin.
• Unable to produce and maintain the free flow of bile.
• Unable to properly synthesise proteins.
• Unable to maintain hepatic cellular integrity.

However, having abnormal results do not necessarily signify liver disease. In some situations, the liver has to work harder than usual and some values may be abnormal. For example, many drugs (antibiotics, non-steroidal anti-inflammatory drugs, statins, antiepileptics, etc.) may slightly alter these values, especially aminotransferases and bilirubin.[11] To consider these changes benign, they must be mild, asymptomatic, and reversible.

Liver function is commonly tested through biochemical markers that provide a valuable and efficient overview of the organ; in other words, they are useful for the diagnosis and management of liver health or disease. 

Liver blood tests usually encompass alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), bilirubin, albumin (ALB), globulins, and total protein (TP). Liver function tests may exclude some of these markers while including others, such as aspartate aminotransferase (AST) or coagulation times (prothrombin time and partial thromboplastin time).[7]

In general, liver function tests at home shed some light on a few subjects:

• Aminotransferases (ALT, GGT, AST) and ALP are useful for identifying liver injury. These markers are commonly found inside hepatocytes (liver cells), especially in the case of ALT.[8]
• Hepatic proteins (albumin, globulins, total protein) are indirect markers of protein production in the liver.[8]
• Bilirubin is a pigment derived from the breakdown of heme-containing proteins, such as haemoglobin. It is useful for determining hepatic clearance.[8]

Liver disease refers to any condition characterised by acute or chronic liver damage, making it unable to function properly. The presence of liver disease following abnormal liver function can often be identified using a liver home test kit.

It can be caused by a wide variety of factors, from alcohol consumption or unhealthy lifestyles to viruses or autoimmune disorders. As the damage persists over time, these conditions progress towards hepatic cirrhosis, which is marked by the formation of scar tissue (fibrosis).

The most common causes of liver disease are:[12]

• Primary liver cancer, commonly a consequence of chronic liver disease.
• Non-alcoholic fatty liver disease, which is related to obesity and metabolic syndrome.
• Alcoholic-related fatty liver disease, caused by regular and excessive alcohol intake.
• Viral hepatitis, caused by becoming infected with hepatitis-causing viruses, such as hepatitis A, B, C, D, and E.
• Autoimmune liver disease, which occurs when the immune system mistakenly attacks the liver.
   

Taking a liver function test at-home is not only a more convenient option but also can be a safer one. At-home blood testing opens the doors to patient-centric care, allowing people to take control of their health. Since its introduction, at-home testing has served an important role in early diagnosis and disease monitoring, enabling patients and doctors to act and plan in a timely manner.

A liver test home kit is excellent for a rapid health check or convenient monitoring. Viral hepatitis, alcohol-related liver disease, and non-alcoholic fatty liver disease are common conditions that are routinely investigated and followed with the help of liver function home tests. 

Some extrahepatic diseases can be suspected or supervised through these tests; for instance, bilirubin is commonly ordered in cases of suspected haemolytic anaemia[9] and albumin is employed during the assessment of nutritional risk in various populations, including the elderly and patients with cancer.[10]